The valvular and ventricular dysfunctions affect the quality life of tens of thousands patients. More than 28,000 deaths in 2001 are caused by cardiomyopathy. However, there is little convenient noninvasive assessment approach for quantifying the severity of the valvular dysfunction for the early to moderate stage patients as an aid for later therapeutic management.
The circulatory system consists of a heart and blood vessels. In its path through the heart, the blood encounters four valves. The valve on the right side that separates the right atrium from the right ventricle has three cusps and is called the tricuspid valve. It closes when the ventricle contracts during a phase known as systole and it opens when the ventricle relaxes, a phase known as diastole.
The pulmonary valve separates the right ventricle from the pulmonary artery. It opens during systole, to allow the blood to be pumped toward the lungs, and it closes during diastole to keep the blood from leaking back into the heart from the pulmonary artery. The pulmonary valve has three cusps, each one resembling a crescent and it is also known as a semi-lunar valve.
The mitral valve, so named because of its resemblance to a bishop's mitre, is in the left ventricle and it separates the left atrium from the ventricle. It opens during diastole to allow the blood stored in the atrium to pour into the ventricle, and it closes during systole to prevent blood from leaking back into the atrium. The mitral valve and the tricuspid valve differ significantly in anatomy. The annulus of the mitral valve is somewhat D-shaped whereas the annulus of the tricuspid valve is more nearly circular.
The fourth valve is the aortic valve. It separates the left ventricle from the aorta. It has three semi-lunar cusps and it closely resembles the pulmonary valve. The aortic valve opens during systole allowing a stream of blood to enter the aorta and it closes during diastole to prevent any of the blood from leaking back into the left ventricle.
In a venous circulatory system, a venous valve is to prevent the venous blood from leaking back into the upstream side so that the venous blood can return to the heart and the lungs for blood oxygenating purposes.
The effects of valvular dysfunction vary. Mitral regurgitation has more severe physiological consequences to the patient than does tricuspid valve regurgitation. In patients with valvular insufficiency it is an increasingly common surgical practice to retail the natural valve, and to attempt to correct the defects. Many of the defects are associated with dilation of the valve annulus. This dilatation not only prevents competence of the valve but also results in distortion of the normal shape of the valve orifice or valve leaflets. A suitable approach for treating an annulus, including repair of a valve, valve replacement, implantation of an annuloplasty ring or annulus tissue shrinkage depends on the detection and determination of the severity of the valvular dysfunction.
Cardiomyopathy is a type of heart diseases in which the heart is abnormally enlarged, thickened and/or stiffened. As a result, the heart muscle's ability to pump blood is usually weakened. The condition typically begins in the walls of the heart's lower chambers, and more severe cases may affect the walls of the upper chambers, as well. This damage to the heart walls inhibits the ability of the heart to function effectively, which commonly results in congestive heart failure. Dilated cardiomyopathy (DCM) is a condition in which the heart's ability to pump blood is decreased because the heart's main pumping chamber, the left ventricle, is enlarged and stiff; this causes a decreased ejection fraction (the amount of blood pumped out with each heart beat). In general, it prevents the heart from relaxing and filling with blood as it should. Over time, it can affect the other heart chambers as well.
Hueb and associates studied the behavior of the mitral valve ring and the left ventricle in dilated cardiomyopathy (J Thorac Cardiovasc Surg 2002; 124:1216-24). They reported in ischemic or idiopathic dilated cardiomyopathy, dilation of mitral ring is proportional and does not exclusively affect the posterior portion. The degree of left ventricular dilation does not determine the degree of dilation of the mitral ring because they are independent processes. It is, therefore, one object of the present invention to provide a method for measuring a patient's Formation number (Fn) and comparing the measured Fn to the baseline data of healthy persons to assess the degree of valvular normality or valvular dysfunction
Therefore, it is one aspect of the present invention to provide a system and method for assessing the patient's valvular dysfunction due to cardiomyopathy or fibrillation by analyzing the data from noninvasive ultrasound scanning or magnetic resonance imaging.